Grinding wheel dressing mechanism



y 8, T941 c. L. OTT ETAL 2,248,463

GRINDING WHEEL mmssme MECHANISM Filed July .22, 193B 2 Sheets-Sheet 1 Snnentors CONRAD 4. 01'1- BURB .B. BEARD HARULD EfifiLS/GER E v Q Y 5 attorney July 8, 1941. c. L. OTT E'I'AL I GRINDING WHEEL DRESSING MECHANISM Filed Jul 22, 1938 2 Sheets-Sheet 2 s m f n. m m nn u W R E m Patented July 8, 1941 GRINDING WHEEL DRESSING MECHANISM! Conrad L. Ott, Detroit, Mich, and Burr B. Beard and Harold E. Balsiger, Waynesboro, Pa., assignors to Landis Tool Company, Waynesboro, Pin, a corporation of Pennsylvania Application July 22, 1938, Serial No. 229,776

(Cl. 125l1) Claims.

Our invention relates to dressing devices for grinding wheels, particularly on machines having two or more wheels of varying diameters mounted on the same spindle.

One object is to provide means whereby the dressing tool may be advanced or retracted automatically as it passes from one wheel to another in order to position it for each diameter.

Another object is to provide means for causing the rate of the traverse movement to be increased as the dresser passes from one wheel to another.

A further object is to provide means whereby Wheels varying considerably in diameter and spaced close together may be dressed automatically and successively.

Figure 1 is a plan view of my device including a diagram of the piping and wiring.

Figure 2 is a rear view of the dressing tool and the switches for same.

Figure 3 is a left hand end elevation of the means for intermittently changing the speed of traverse.

Figure 4 is a partial left end elevation showing the means for automatically operating the reversing switch.

In the drawings numeral I5 indicates a base member mounted on the bed of a machine at the rear of the grinding wheels, upon which is slidably mounted a support H for a dressing mechanism. A cylinder l2 secured to said base contains a piston !3 which is connected to support l I by connecting rod M for traversing same along the base It. Support II has a cylindrical portion I5 in which a diamond bar It with a diamond is slidably mounted for movement toward and from the grinding wheels ll, l8 and I9. Wheels I? and I8 differ considerably in diameter and are mounted close together. The portion of said diamond bar extending beyond said support II is enclosed in a housing 26. A cylinder 2! on the side of cylindrical portion l5 contains a piston 22. Said piston is connected to housing 25 thru piston rod 23 and serves to effect a rapid adjustment of the diamond 25 as it passes from wheel H to wheel I8 or vice versa. A feeding movement of the diamond is provided by a handwheel 25 and screw mechanism similar to that disclosed in co-pending application Speed control mechanism, Serial No. 203,668 filed April 22, 1938. Said feeding mechanism may be actuated by pressure actuated pawl 21 in engagement with a ratchet 28 on the handwheel shaft. Said pawl may be reciprocated by a piston 29 in cylinder 59. A second pawl and ratchet mechanism simii larly operated serves to advance the grinding wheels by the amount to be removed by dressing. This mechanism consists of a ratchet wheel 35 and a pawl 36. Said pawl is pivotally supported in a slotted piston 31. Said piston may be reciprocated by fluid under pressure in cylinder 38.

Fluid under pressure is supplied simultaneously to cylinders I2, 30 and 38 from valve 40. Said valve may be moved in one direction manually by a knob ll and in the opposite direction by a spring 52. A collar 43 on stem 44 of said valve is engaged bya latch 45 and held thereby in the position to which it has been moved by hand.

Fluid is supplied to said valve thru line 53 from pump 5| and distributed thru lines 52 and 53 to cylinder 12, lines 54 and 55 to cylinder 35 and lines 56 and 5'! to cylinder 38.

Pump 5i also supplies fluid under pressure thru line 60 to valve 6| from which it is directed thru line 52 to cylinder 2!. A drain line 63 permits removal from cylinder 2! of any fluid which may leak past piston 22. Valve BI is actuated in one direction by a solenoid E i and in the opposite direction by a spring 65.

Fluid supplied to line 52 may enter cylinder l2 without any restriction thru valve 61. If valve 61 is closed fluid must pass thru throttle valve 66. The means for actuating valve 66 includes a shaft Ill rotatably mounted in bearing brackets H and 12 on base it. A series of tongues l5, l6 and H are adjustably secured to said shaft at spaced intervals. A roller 78 is mounted on support H in such a manner that it extends in overlapping relation to said tongues with its lower side below the upper surface of said tongues. At the valve end of shaft 75, said shaft extends thru the bearing H. To this extended portion of said shaft is attached another tongue in position to engage the end of the stem 18 on valve 5']. Said valve is moved in the opposite direction by spring 68. Housing 28 and diamond bar it are urged toward a withdrawn position by a back lash mechanism consisting of a shaft 525 about which is Wound a spring E25 and a chain l2? attached to some suitable part of the diamond bar H3 or associated parts. The movement in this direction is limited by a shoe H3 on said housing engaging a profile bar lit having a locating surface I l I for positioning diamond 25 to dress wheel it. Another locating surface H2 serves to position the diamond 25 for dressing wheel l d. An adjustable screw l l5 limits the forward movement of the piston 22 and locates the diamond 25 for dressing wheel ll.

A limit switch 80 is attached to the base If] on the side opposite the grinding wheels. A lever 8| is rotatably mounted on a shaft 82 which extends thru a portion of said base It. Said lever is yieldingly held against counter-clockwise movement by spring 86. At the other end of said shaft is secured an arm 83. In the end of said arm is a roller 85 in a position substantially parallel to shaft 82. A cam bar 85 is secured to support ll. Roller 84 is held in contact with said bar by spring 86.

Another switch 90 is mounted on base l and adapted to be actuated by pivoted dog 88 to energize solenoid 9|. This switch is a safety device to prevent an extended traverse of the diamond in its forward position. A push button switch 92 in parallel with switch 90 is the normal means for energizing solenoid 9| to reverse the traverse movement. Thus, solenoid 9| may be energized thru either of said switches. Said dog is pivotally mounted in the bearing housing of handwheel 26. A spring tends to rotate said dog in a clockwise direction which movement is limited by housing 29 or diamond bar It. When stop H3 engages bar I It at the left hand end thereof, housing 29 and dog 88 will have moved so that said dog is aligned with the roller on the arm of switch 99. Movement of the diamond bar to the rear by means of handwheel 26 will be effective to rotate said dog out of position to engage the roller of switch 90.

Current is supplied to said solenoids E4 and M from lines IOI and Hi2. Line If)! leads direct to solenoid 54. Line Hi3, a branch of line Mil, leads direct to solenoid 91. A return line ltd passes thru the push button switch 92 and returns to supply line W2. A branch 185 from said return line by-passes said push button switch and returns to line it after passing thru limit switch at. The return line I06 from solenoid B l passes thru switch 86 before returning to line I92.

Operation The normal inoperative position of the dressing tool is at the right end of its travel. In order to initiate the dressing operation the operator shifts valve 48 to the left against spring 42. Latch 45 holds the valve in this position and fluid under pressure is directed thru line 52 to the right end of cylinder [2 causing piston l3 and support H to move toward the left. At the same time fluid is also directed thru line 54 to cylinder 38 to actuate pawl 2i to feed diamond toward the grinding wheels and thru line 56 to cylinder 38 to actuate pawl 36 and ratchet to effect a movement of the grinding wheel to compensate -or the amount removed by wear and by dressing. When valve is shifted in the opposite direction, fluid is directed to the other ends of cylinders 30 and 38 and the two feed pawls are reset by returning them to their original position. The rate of movement of support I! depends upon whether the fluid under pressure enterin said cylinder passes first thru unrestricted valve 6'! or thru restricted valve 65. The tongues l5, l3 and l'T are spaced so that ear-h space is opposite a grinding wheel. When the dressing operation. is initiated, roller 78 is in contact with tongue 11 and valve 6'! is thus positioned to permit an unrestricted flow of fluid to cylinder i2. Support II will move rapidly to the left until roller I8 reaches the space between tongues l5 and T! when diamond 25 will be positioned by locating surface H2 and valve 6'! will be released and shifted by spring 68 to shut off the flow of fluid there thru. Said fluid must then pass thru valve 66 and thus the rate of movement of support H is reduced while diamond 25 passes across wheel l9. After said diamond has passed across wheel [9, roller 18 rides over tongue 16 depressing same and shifting valve 61 to open position so that diamond 25 may pass from wheel l9 to wheel 8 at a high speed. Surface Ill on profile bar llil will locate the diamond for wheel [8, and roller 18 passing off tongue 16 will initiate the slow, dressing traverse movement.

As the diamond passes off wheel 18, pin 81 in arm 83 will be guided in such a manner as to rotate shaft 82 in a clockwise direction viewed from the front of the machine. Lever 8| will thus be rotated against the action of spring 86 and will depress the arm of switch to break the circuit there thru. This will deenergize solenoid 64 and permit spring 65 to shift valve Bl to direct fluid under pressure thru line 63 to cylinder 2i and shift diamond 25 toward wheel l'l until stopped by adjusting screw H5.

After diamond 25 has passed across wheel ll the operator presses push button switch 92 to energize solenoid 91 which withdraws latch 45 and permits spring 42 to shift valve 40 to the right. If the operator fails to close switch 92, and the diamond remains in advanced position, dog 88 will close switch 90 to energize solenoid 9|. Fluid under pressure is directed thru line 53 to the left end of cylinder IE to move piston i3 and support I I to the right. During the traverse movement to the right the same control is exercised over the speed except that the exhaust fluid instead of the incoming fluid is controlled. After the diamond has passed across wheel I! switch 80 is opened and solenoid (i4 deenergized. Spring 65 shifts valve 6| to a position to cut off the supply of fluid under pressure and to connect line 62 with exhaust I20. As the pressure on piston 22 is released, the back lash mechanism moves housing 20 and diamond 25 until shoe H3 engages the locating surface again. The remainder of the traverse movement is the reverse of the movement to the left. At the end of the movement to the right, support i i comes to rest against a positive stop, not shown, and remains in this position until valve M is again actuated.

In case it is desired to continue the movement of the dresser to the left for the purpose of placing the diamond bar in a position where the diamond may be easily replaced, it is necessary to run the diamond bar It back by means of handwheel 26 far enough to engage dog 88 and swing it out of position to operate switch 90.

In this position the diamond bar will be able to pass thru an opening in the wheel fender to a position where the operator may replace the diamond.

We claim:

1. A mechanism for dressing a plurality of axially aligned grinding wheels comprising a base member, a dressing tool slidably mounted for movement longitudinally and transversely of said base, a contour bar for limiting said transverse movement in one direction, yielding means for holding said dressing tool against said contour bar, power means for moving said dressing tool in the opposite direction, a positive stop for limiting said movement in said opposite direction and means operable at a predetermined point in said longitudinal movement for controlling the operation of said power means.

2. A mechanism for dressing a plurality of axially aligned grinding wheels comprising a base member, a dressing tool slidably mounted for movement longitudinally and transversely of said base, a contour bar for limiting said transverse movement in one direction, yielding means for holding said dressing tool against said contour bar, power means for-moving said dressing tool in the opposite direction, an adjustable positive stop for limiting said movement in said opposite direction, means operable at a predetermined point in said longitudinal movement for controlling the operation of said power means, fluid pressure means for efiecting said longitudinal movement whereby to subject said wheels successively to said dressing tool and a valve for varying the speed of said movement during each dressing operation.

3. A mechanism for dressing a plurality of axially aligned grinding wheels of different radii where the space between some of the wheels is greater than the difierence in radius and where the space between other wheels is equal to or less than the difierence in radius comprising a base member, a dressing tool slidably mounted for movement longitudinally and transversely of said wheels, a cam bar for effecting said transverse movement between said widely spaced wheels, and a motor for efiecting said transverse movement between said closely spaced wheels.

4. A mechanism for dressing a plurality of grinding wheels of different radii where the space between some of the wheels is greater than the difierence in radius and where the space between other wheels is equal to or less than the difference in radius comprising a base member, a dressing tool slidably mounted for movement longitudinally and transversely of said wheels, cam surfaces for locating said dressing tool transversely for dressing said widely spaced wheels, and a motor for positioning said dressing tool transversely for dressing said closely spaced wheels.

5. A mechanism for dressing a plurality of axially aligned grinding wheels comprising a base member, a dressing tool slidably mounted for movement longitudinally and transversely of said base, a contour bar for limiting said transverse movement in one direction, yielding means for urging said dressing tool in one direction relative to the contour bar, power means for moving said dressing tool in the opposite direction, a positive stop for limiting said movement in said opposite direction, and means operable at a predetermined point in said longitudinal movement for controlling the operation of said power means.

CONRAD L. OTT. BURR B. BEARD. HAROLD E. BALSIGER. 

